The Guanganmen area is the locality of the ancient Jicheng city (the earliest city site in Beijing). Based on the geomorphological analysis and the several kinds of experiments for the samples collected from the geotechnical profile in the construction site of Guangyi Building in Guanganmen area, the reconstructions of palaeogeomology in this area were conducted. The results show that the location of the ancient Jicheng city was just the highland, which developed since the Holocene, beside the river, where the channel of Yongding River has been passed through about 22000 years ago. The climate in this area has changed from the cool and wet environment (sparse-wood grassland was developed) and the following arid environment (grassland vegetation was developed) in the late Late-Pleistocene to the warm and wet environment (sparse-wood grassland was developed) and the following cool and wet conditions (meadow vegetation was developed) during the Holocene.

In a long time, a series of environmental geology calamities were caused by excess drawing ground-water in Suxichang area. All these calamities not only brought huge economic loss but also affected the development of cities and deteriorated investment environment in this area. So, it is very important for the economic sustainable development in this area to adopt practical measures to prevent and cure the environmental geology calamities.

The Dongfang Plaza cultural site, located in Wangfujing, Beijing, is the first found of late paleolithic relic in Beijing plain. The process of climate change during 26-14ka B.P. will be discussed in this paper, based on the analysis of the sedimentary facies characters and paleo-environment indexes such as clay mineral, chemical element and spore-pollen of the sediment samples collected from the middle-part of the stratigraphic profile (including upper and lower cultural layers) of the Dongfang Plaza cultural site. The landform on which ancient human activity relic located was interfluvial floodplain on Yongding River Alluvial Fan. The result of analysis shows that the climate of the period during which these strata were formed was mainly dry and cold, and the pollen of herbs is predominant. In the later part of this period the temperature and humidity increased a little, especially between the two cultural layers there was a short but clear section of wet and warm climate and a temperate forest steppe landscape existed. So it can be concluded that after the lower cultural stratum was formed, the flood became greater due to the wetter weather and bigger river discharge, and the ancient people were forced to move to other higher places. Later the climate began to dry and human activities appeared here again. In such a way two cultural strata were formed. Cultural sites of dry-cold late Late-Pleistocene have been found in Beijing, Inner Mongolia Autonomous Region, Heilongjiang province and other places, which indicates that the people of late Late-Pleistocene already had the ability to defend the dry-cold weather.

The sedimentary characteristics and facies of the cultural layers in the late Paleolithic period of the late Late-Pleistocene in the Wangfujing Oriental Plaza site were studied based on the comparison and analysis of the typical sedimentation profile of the site and more than 150 stratigraphic data. The paleo-geomorphic surfaces during the periods of 2.2×10⁴ a B.P. were rediscovered. The study suggests that the ancients must have acted in the sandy islands of alluvial fans, which were evolved in relatively steady water flows during the interglacial stage with slightly warming in the last glacial epoch. The cause of the absent of human activities between the upper and lower cultural layers in an interval of about 3.14×10³ a has also been discussed in detail. It is concluded that this was resulted from the strengthening and unstable water flow. The potential former settlements or camping sites of the ancients prior to moving to this area are also discussed. It is suggested that they might came from other higher dissected old alluvial fan platforms evolved at the same period or earlier in the western part of the plain. These results provide evidences for the reconstruction of the geomorphic environment of Beijing plain during the Late Pleistocene and the study of prehistoric human history.